This invention relates to a sealing arrangement for tiltable and pivotal windows of the kind in which both the frame and sash have abutment surface sections facing in opposite directions on either side of the axis of rotation, at least one of the abutment surfaces being provided with a weather strip to improve the tightness in the closed position of the window.
Such a sealing arrangement is for instance known from the specification of British Pat. No. 877,302 which makes it clear that in windows of the kind concerned (i.e. with a window sash which is rotatable about a horizontal or vertical axis positioned between, ordinarily approximately midway between, the frame members parallel to the axis) a particular sealing problem between frame and sash arises in the area of the axis where two joints intersect, viz. the longitudinal joint between the associated frame and sash members, and the transverse joint between the opposite ends of the rabbets or abutment strips of the frame and the sash, respectively. The patent specification discloses a solution including the use of a channel-shaped weather strip composed of two pieces, one of which has one longitudinal edge portion inserted between the sash member and its rabbet or abutment strip while its other longitudinal edge portion seals against the frame when the window is closed, and vice versa as far as the other weather strip piece is concerned. The weather strip also overbridges the said transverse joint in the closed position of the window, either in the way that its two pieces overlap each other at this joint or by providing a tight end abutment between both weather strip pieces. It is, however, considered a drawback that the weather strip must necessarily consist of two separate pieces, because on either side of the region of the axis, it must be secured to the stationary frame and to the movable sash, respectively.
FIG. 4 of the British Pat. No. 988,469 illustrates another proposal for solving the particular sealing problem in tiltable and pivotable windows, viz. by using a resilient weather strip of T-shaped cross-section, the head portion of the strip being continuous while its web portion is cut through at the axial region of the window and on opposite sides thereof is secured to the frame portion and to the sash portion, respectively. A primary condition of realizing this proposal is that the axis of the window passes through or at any rate is spaced only slightly from the head portion of the T-shaped weather strip as, otherwise, this portion will be longitudinally stretched or compressed rather strongly by maximum tilting or rotation of the window sash in the frame. Such an axis positioning may however cause drawbacks in other respects, in particular if the window shall be provided with external cover rails which in the closed position should overlap each other in the area of the axis. Even with the indicated positioning of the axis in relation to the head portion of the weather strip member, this portion will however be strongly deformed by bending when the window opens, thereby entailing that the lifetime of the weather strip may be shorter than intended.